Verify an Argon2 Password with a Secret and Memory Guard

Demonstrates Crypt2.Argon2VerifyPassword when the hash was created with a secret (pepper) or ad, and the use of maxMemoryKb to guard against untrusted hash strings.

import com.chilkatsoft.chilkat2.Crypt2;
import com.chilkatsoft.chilkat2.JsonObject;

public class ChilkatExample {

    public static void main(String[] args) {
        Crypt2 crypt = new Crypt2();

        // The password should come from a secure source rather than being hard-coded.
        String password = "correct horse battery staple";

        String phcHash = "$argon2id$v=19$m=131072,t=4,p=2$c29tZXJhbmRvbXNhbHQ$3fJ7v1qKcVJ0lHqXjBQZ8mYm3sNTfSPRt0bqDl9kEyM";

        // When the hash was created with a secret (pepper) or ad, the same values must be supplied to verify.
        // Only the secret, ad, encoding, passwordCharset, and maxMemoryKb members of the options are used;
        // everything else is ignored.
        JsonObject json = new JsonObject();
        json.updateString("secret", "application-wide-pepper");
        json.updateString("secretEncoding", "utf-8");

        // maxMemoryKb guards against a hash from an untrusted source claiming an enormous memory cost.  The
        // memory cost is taken from the hash string, so this limit is checked before any memory is allocated.
        // It defaults to 2 GB.
        json.updateInt("maxMemoryKb", 262144);

        // Argon2VerifyPassword returns 1 if the password matched, 0 if it did not match, and -1 if the
        // verification could not be performed.  Always test for a match with == 1.
        int verifyResult = crypt.argon2VerifyPassword(password, json.emit(), phcHash);
        if (verifyResult == 1) {
            System.out.println("The password is verified.");
        } else {
            if (verifyResult == 0) {
                System.out.println("The password does not match.");
            } else {
                System.out.println("The verification could not be performed: " + crypt.getLastErrorText());
            }
        }
    }
}